Bridge clip tissue connector apparatus and methods

ABSTRACT

A novel bridge clip tissue connector includes two clips separated by a bridge portion. The clips allow for the connecting of tissue at two positions that are maintained by the bridge portion. The connector can be used for performing a wide variety of surgical procedures, including anastomosis and a horizontal mattress suture-like connection.

CROSS-REFERENCE TO RELATED DOCUMENTS

The present application is a continuation-in-part of copending patentapplication Ser. No. 09/260,623, filed Mar. 1, 1999.

FIELD OF THE INVENTION

The present invention relates to instruments and methods for connectingbody tissues, tissue and prostheses, tissue and graft or any combinationthereof.

BACKGROUND OF THE INVENTION

Minimally invasive surgery has allowed physicians to carry out manysurgical procedures with less pain and disability than conventional,open surgery. In performing minimally invasive surgery, the surgeonmakes a number of small incisions through the body wall to obtain accessto the tissues requiring treatment. Typically, a trocar, which is apointed, piercing device, is delivered into the body with a cannula.After the trocar pierces the abdominal or thoracic wall, it is removedand the cannula is left with one end in the body cavity, where theoperation is to take place, and the other end opening to the outside. Acannula has a small inside diameter, typically 5-10 millimeters, andsometimes up to as much as 20 millimeters. A number of such cannulas areinserted for any given operation.

A viewing instrument, typically including a miniature video camera oroptical telescope, is inserted through one of these cannulas and avariety of surgical instruments and refractors are inserted throughothers. The image provided by the viewing device may be displayed on avideo screen or television monitor, affording the surgeon enhancedvisual control over the instruments. Because a commonly used viewinginstrument is called an “endoscope,” this type of surgery is oftenreferred to as “endoscopic surgery.” In the abdomen, endoscopicprocedures are commonly referred to as laparoscopic surgery, and in thechest, as thoracoscopic surgery. Abdominal procedures may take placeeither inside the abdominal cavity (in the intraperitoneal space) or ina space created behind the abdominal cavity (in the retroperitonealspace). The retroperitoneal space is particularly useful for operationson the aorta and spine, or abdominal wall hernia.

Minimally invasive surgery has virtually replaced open surgicaltechniques for operations such as cholecystectomy and anti-refluxsurgery of the esophagus and stomach. This has not occurred in eitherperipheral vascular surgery or cardiovascular surgery. An important typeof vascular surgery is to replace or bypass a diseased, occluded orinjured artery. Arterial replacement or bypass grafting has beenperformed for many years using open surgical techniques and a variety ofprosthetic grafts. These grafts are manufactured as fabrics (often fromDACRON® (polyester fibers) or TEFLON® (fluorocarbon fibers)) or areprepared as autografts (from the patient's own tissues) or heterografts(from the tissues of animals) or a combination of tissues,semi-synthetic tissues and or alloplastic materials. A graft can bejoined to the involved artery in a number of different positions,including end-to-end, end-to-side, and side-to-side. This attachmentbetween artery and graft is known as an anastomosis. Constructing anarterial anastomosis is technically challenging for a surgeon in opensurgical procedures, and is almost a technical impossibility usingminimally invasive techniques.

Many factors contribute to the difficulty of performing arterialreplacement or bypass grafting. See generally, Wylie, Edwin J. et al.,Manual of Vascular Surgery, (Springer-Verlag New York), 1980. One suchfactor is that the tissues to be joined must be precisely aligned withrespect to each other to ensure the integrity and patency of theanastomosis. If one of the tissues is affixed too close to its edge, thesuture can rip through the tissue and impair both the tissue and theanastomosis. Another factor is that, even after the tissues are properlyaligned, it is difficult and time consuming to pass the needle throughthe tissues, form the knot in the suture material, and ensure that thesuture material does not become tangled. These difficulties areexacerbated by the small size of the artery and graft. The arteriessubject to peripheral vascular and cardiovascular surgery typicallyrange in diameter from several millimeters to several centimeters. Agraft is typically about the same size as the artery to which it isbeing attached. Another factor contributing to the difficulty of suchprocedures is the limited time available to complete the procedure. Thetime the surgeon has to complete an arterial replacement or bypass graftis limited because there is no blood flowing.

through the artery while the procedure is being done. If blood flow isnot promptly restored, sometimes in as little as thirty minutes, thetissue the artery supplies may experience significant damage, or evendeath (tissue necrosis). In addition, arterial replacement or bypassgrafting is made more difficult by the need to accurately place andspace many sutures to achieve a permanent hemostatic seal. Preciseplacement and spacing of sutures is also required to achieve ananastomosis with long-term patency.

Highly trained and experienced surgeons are-able to perform arterialreplacement and bypass grafting in open surgery using conventionalsutures and suturing techniques: A suture has a suture needle that isattached or “swaged on” to a long, trailing suture material. The needlemust be precisely controlled and accurately placed through both thegraft and artery. The trailing suture material must be held with propertension to keep the graft and artery together, and must be carefullymanipulated to prevent the suture material from tangling. In opensurgery, these maneuvers can usually be accomplished within thenecessary time frame, thus avoiding the subsequent tissue damage (ortissue death) that can result from prolonged occlusion of arterial bloodflow.

A parachuting technique may be used to align the graft with the arteryin an end-to-side anastomosis procedure. One or multiple sutures areattached to the graft and artery and are used to pull or “parachute” thegraft vessel into alignment with an opening formed in a sidewall of theartery. A drawback to this procedure is the difficulty in preventing thesuture from tangling and the time and surgical skill required to tieindividual knots when using multiple sutures. Due to space requirements,this procedure is generally limited to open surgery techniques.

The difficulty of suturing a graft to an artery using minimally invasivesurgical techniques has effectively prevented the safe use of thistechnology in both peripheral vascular and cardiovascular surgicalprocedures. When a minimally invasive procedure is done in the abdominalcavity, the retroperitoneal space, or chest, the space in which theoperation is performed is more limited, and the exposure to the involvedorgans is more restricted, than with open surgery. Moreover, in aminimally invasive procedure, the instruments used to assist with theoperation are passed into the surgical field through cannulas. Whenmanipulating instruments through cannulas, it is extremely difficult toposition tissues in their proper alignment with respect to each other,pass a needle through the tissues, form a knot in the suture materialonce the tissues are aligned, and prevent the suture material frombecoming tangled. Therefore, although there have been isolated reportsof vascular anastomoses being formed by minimally invasive surgery, nosystem has been provided for wide-spread surgical use which would allowsuch procedures to be performed safely within the prescribed timelimits.

As explained above, anastomoses are commonly formed in open surgery bysuturing together the tissues to be joined. However, one known systemfor applying a clip around tissues to be joined in an anastomosis isdisclosed in a brochure entitled, “VCS Clip Applier System”, publishedin 1995 by Auto Suture Company, a Division of U.S. Surgical Corporation.A clip is applied by applying an instrument about the tissue in anon-penetrating manner, i.e., the clip does not penetrate through thetissues, but rather is clamped down around the tissues. As previouslyexplained, it is imperative in forming an anastomosis that tissues to bejoined are properly aligned with respect to each other. The disclosedVCS clip applier has no means for positioning tissues. Before the clipcan be applied, the tissues must first be properly positioned withrespect to each other, for example by skewering the tissues with aneedle as discussed above in common suturing techniques or with forcepsto bring the tissues together. It is extremely difficult to perform suchpositioning techniques in minimally invasive procedures.

Therefore, there is currently a need for other tissue connectingsystems.

SUMMARY OF THE INVENTION

The present invention involves apparatus and methods for connectingmaterial, at least one of which is tissue. The invention may, forexample, be used to secure one vessel to another, such as in a vascularanastomosis.

According to one aspect of the invention, a tissue connector assembly isprovided comprising a surgical fastener, such as a surgical clip, afirst tissue-piercing member and a second tissue-piercing member. Thefastener may be adapted to assume a loop configuration. The fastener hasa first end portion and a second end portion. The first tissue-piercingmember is coupled to the first end portion and the secondtissue-piercing member is coupled to the second end portion. Themultiple piercing member construction facilitates threading ends of theassembly from inner to outer Walls of material, such as tissue, whichmay eliminate or minimize the possibility of dislodging material fromthe inner wall of a vessel, for example.

According to another aspect of the invention, a flexible member, such asa suture, may be provided between at least one piercing member and thefastener to facilitate threading the fastener and/or “parachute”techniques, for example.

According to another aspect of the invention, synchronized piercingmember release mechanisms may be provided. In one embodiment, the tissueconnector assembly may include a first coupling, which couples the firsttissue piercing member and first end portion of the surgical fastener,and a second coupling, which couples the surgical fastener second endportion and second piercing member. The first coupling releases theother coupling in response to releasing the first coupling. According toone aspect of this embodiment, multiple tissue piercing members may bedecoupled from the surgical fastener with one release actuator.According to another aspect, the piercing members may be decoupledessentially simultaneously.

According to yet another aspect of the invention, a tissue connectorassembly is provided for joining tissues as a “bridge clip” thatincludes a surgical fastener having two surgical clips connected by abridge. In one embodiment the two clips are biased into an openconfiguration, and can close through a release mechanism. In analternative embodiment, each clip has one release mechanism and one coilsurrounding the clip to individually bias the clips in an openconfiguration. In yet another alternative embodiment, each clip has onerelease mechanism, and a single: coil is connected to both releasemechanisms to bias both clips. In a preferred embodiment, each clip isattached to a piercing member through a length of a flexible member.

According to another aspect of the present invention a tissue connectorassembly is provided for attaching tissue. In one embodiment theassembly includes a surgical fastener having two self-closing clipsseparated by a bridge portion and a release mechanism to actuate theself-closing clips. Another embodiment provides a surgical fastenerhaving two clips, at least one of which is self-closing, separated by abridge portion and coupled to tissue piercing members.

According to another aspect of the invention, a bridge clip is providedto facilitate attaching tissue using a technique such as parachuting.With both clips in the open configuration and attached to theirrespective piercing member, each piercing member is used to pierce oneside of a tissue, effectively positioning the bridge against the tissue.After a second set of piecings on a second tissue, the first tissue canbe guided onto the second tissue. With the clips threaded through bothtissues, the release mechanism is actuated, securing the two tissues attwo slightly displaced locations. In yet another aspect of theinvention, a bridge clip is provided to attach tissues using a techniquesimilar to a horizontal mattress suture.

The above is a brief description of some deficiencies in the prior artand advantages of the present invention. Other features, advantages, andembodiments of the invention will be apparent to those skilled in theart from the following description, accompanying drawings, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective of a tissue connector assembly constructed inaccordance with the principles of the present invention;

FIG. 2A is a partial sectional view illustrating an alternateconstruction of flexible member 18 of FIG. 1;

FIG. 2B is a partial sectional view illustrating yet anotherconstruction of flexible member 18 of FIG. 1;

FIGS. 3A, 3B and 3C show a fastener which can be used with the tissueconnector assembly of FIG. 1, where FIG. 3A is a top view of thefastener in a closed position, FIG. 3B is a side view of the fastener ofFIG. 3A, and FIG. 3C is an enlarged view of the fastener of FIG. 3A inan open position;

FIG. 4 is a top view of another fastener configuration, which can beused with the tissue connector assembly of FIG. 1;

FIGS. 5A and 5B show yet another fastener configuration which can beused with the tissue connector assembly of FIG. 1, where FIG. 5A showsthe fastener in a closed position and FIG. 5B is a side view of thefastener of FIG. 5A;

FIG. 6 is top view of yet a further configuration of a fastener that canbe used with the tissue connector assembly of FIG. 1 with the fastenerin a closed position;

FIGS. 7A, 7B and 7C illustrate a release mechanism which can be usedwith any of the fasteners described above and the tissue connectorassembly of FIG. 1, where FIG. 7A shows the restraining device incross-section and in a locked position, FIG. 7B is a transversecross-sectional view of the restraining device taken in a plane alongline 7B-7B of FIG. 7A, and FIG. 7C is a cross-sectional view of therestraining device of FIG. 7A in an unlocked position;

FIGS. 8A, 8B and 8C illustrate another release mechanism which can beused with any of the fasteners described above and the tissue connectorassembly of FIG. 1, where FIG. 8A shows the restraining device incross-section and in a locked position, FIG. 8B is a transversecross-sectional view of the restraining device taken in a plane alongline 8B-8B of FIG. 8A, and FIG. 8C is a cross-sectional view of therestraining device of FIG. 8A in an unlocked position;

FIGS. 9A-9E illustrates yet another release mechanism which can be usedwith any of the fasteners described above, where FIG. 9A shows aperspective view of the retaining device coupled with a fastener, FIG.9B is a sectional view of the retaining device of FIG. 9A, FIG. 9C is atransverse cross-sectional view of the restraining device taken alongline 9C-9C in FIG. 9B, FIGS. 9D and 9E are perspective and end views ofthe restraining device, respectively, showing the device depressed forrelease of the fastener; and FIG. 9F shows the retaining device of FIG.9A with an adapter for coupling to the other end of the fastener;

FIGS. 10A-10C show a synchronized fastener release system, where FIGS.10A and 10C are partial sectional views of the system in a coupled anddecoupled state, respectfully, and FIG. 10B is a sectional view takenalong lines 10B-10B in FIG. 10A;

FIGS. 10D-10F show another synchronized fastener release system whereFIGS. 10D and 10E are partial sectional views of the system in a coupledand decoupled state, respectfully, and FIG. 10F is a transversecross-sectional view taken along line 10E-10F in FIG. 10E;

FIGS. 11A and 11B are partial sectional views of another piercing memberand/or suture release mechanism in a coupled and decoupled state,respectfully;

FIGS. 12A and 12B are partial sectional views of a further piercingmember and/or suture release mechanism in a coupled and decoupled state,respectfully;

FIGS. 13A and 13B are partial sectional views of yet another piercingmember and/or suture release mechanism in a coupled and decoupled state,respectfully;

FIG. 14A is a front view of a another embodiment of a tissue connectorassembly of the present invention;

FIG. 14B is a sectional view of a piercing member and release mechanismcombination, which can be used in the embodiment, illustrated in FIG.14A;

FIG. 15 is a front view of a lateral tissue connector, which can be usedin conjunction with any of the assemblies described above;

FIGS. 16A-16D diagrammatically illustrate a method of aligning andconnecting graft and target vessels with the tissue connector assemblyof FIG. 1, where FIG. 16A shows two such tissue connector assembliesthreaded through a graft and target vessel, FIG. 16B shows a furtherstep in connecting the graft and target vessel with the tissue connectorassembly fastener is positioned in the target vessel, FIG. 16C shows yeta further step where the graft has been brought into position over theopening formed in the target vessel and the tissue connector assemblyfastener positioned through the walls of the graft and target vessel andFIG. 16D shows the fasteners released from the tissue connector assemblyof FIG. 1 and securing the graft and target vessel together withadditional laterally disposed fasteners;

FIG. 16E is a partial sectional view of the graft and target vesselswith the tissue connector assembly fasteners of FIG. 1 in place prior toplacement of additional lateral fasteners;

FIG. 16F is an enlarged view of the tissue connection within line 16F ofFIG. 16E;

FIG. 17 is a perspective of a bridge clip tissue connector assembly ofthe present invention;

FIG. 18 is a perspective view of the fastener of FIG. 17, in which thefastener has been released from the tissue connector assembly and is ina closed position;

FIGS. 19A-19C diagrammatically illustrate a method of approximatinggraft and target vessels with the tissue connector assemblies of FIGS. 1and 17, where FIG. 19A shows the tissue connector assembly of FIG. 17threaded through the toe of a graft vessel and target vessel union, FIG.19B shows a further step in connecting the graft and target vessels withthe fastener of FIG. 17 connecting the toe of the graft and threeconnector assemblies of FIG. 1 in various states of connecting the graftand target vessels, and FIG. 19C shows yet a further step where tissueconnector assemblies of FIG. 1 are shown securing the remainder of thevessel edges; and

FIG. 20A-20B are a top and side view, respectively, of a bridge clip asused as a horizontal mattress suture.

Corresponding reference characters indicate corresponding elementsthroughout the drawings.

DESCRIPTION OF THE INVENTION

The present invention generally involves methods and devices formanipulating, aligning and/or connecting tissues, tissue and prosthesis,tissue and graft, or any combination thereof. As used herein, the termgraft includes any of the following: homografts, autologous grafts,xenografts, allografts, alloplastic materials, and combinations of theforegoing. Tissue connector assemblies are disclosed, which, forexample, may be used in vascular surgery to replace or bypass adiseased, occluded, or injured artery by connecting a graft vessel to acoronary artery or vein in an anastomosis as shown in FIGS. 16A-F or inFIGS. 19A-C. Assemblies constructed in accordance with the invention maybe used in open surgical procedures or in minimally invasive orendoscopic procedures for attaching tissue located in the chest,abdominal cavity, or retroperitoneal space. It should be understood,however, that these examples are provided for illustration and are notintended to limit the scope of the invention.

Tissue connecting assemblies and methods are disclosed in copending U.S.patent application Ser. Nos. 09/089,884 and 09/090,305, both entitledTissue Connector Apparatus and Methods and having a filing date of Jun.3, 1998. The entirety of the disclosures of the cited '884 and '305applications is hereby incorporated herein. One aspect of the presentinvention is the provision of multiple tissue piercing members. Morespecifically, tissue connecting assemblies constructed according to thepresent invention generally include a plurality of tissue piercing orpenetrating members coupled to a surgical fastener. The multiplepiercing member construction facilitates threading ends of the assemblyfrom inner to outer wall(s) of material, such as tissue, which mayeliminate or minimize the possibly of dislodging material, such asplaque, from the inner wall of calcified arteries, for example, as willbecome more apparent from the description provided below. In a preferredembodiment, two piercing members, each of which may comprise a needle,are releasably coupled to a fastener. One or both of the piercingmembers may be attached to a flexible member, such as a suture, which inturn is releasably coupled to the fastener. Double and single flexiblemember embodiments are illustrated in FIGS. 1 and 14, respectively. Thecoupling between the flexible member (and, thus, the piercing member)and the fastener may be constructed to actuate closure of the fastenerupon release of the flexible member (or piercing member). For example,the coupling may hold a compression spring (which is positioned around afastener) in a compressed state to brace the fastener open andreleasably lock or secure the fastener to the flexible member (orpiercing member).

A second double flexible member embodiment, also known as a dual clipassembly or as a bridge clip assembly, is illustrated in FIG. 17. Thisembodiment differs from the previous embodiments in that the fastenerincludes two clips separated by a bridge portion. Each clip isreleasably attached to one flexible member and one piercing member. Thebiasing of each of the clips and the releasable coupling of the clips tothe flexible member is similar to that of the previous embodiments. Thefastener of this embodiment is particularly useful in facilitatingtissue attachments, such as in guiding and aligning one tissue forattachment to a second tissue or for performing a horizontal mattresssuture.

FIG. 1 illustrates one embodiment of a tissue connector assembly inaccordance with the present invention. Referring to FIG. 1, a tissueconnector assembly 11, which generally comprises tissue piercing orpenetrating members 16 and 17, flexible members 18 and 19, and afastener 20 (e.g., a surgical clip) is shown. A restraining device,generally indicated at 24 and comprising a spring (or coil) 26 and alocking device (or coupling member) generally indicated at 28, isconnected to fastener 20 for holding the fastener in a deformed or openconfiguration as will be further described below. Although a particularfastener and accompanying restraining device is shown in FIG. 1, itshould be understood that any suitable fastener can be used, includingbut not limited to the alternate fastener configurations describedbelow. For example, the fastener may be a plastically deformable clip ormay comprise two or more parts, at least one of which is movablerelative to the other part, such as with a hinged clip. Further, otherpiercing member release mechanisms can be used with or withoutrestraining devices depending on the fastener construction.

Each of penetrating or piercing members 16 and 17 may be in the form ofa needle (such as a 7-0 or 8-0 needle) having a sharp pointed tip (30 or31) at its distal end for penetrating tissue. Members 16 and 17 may bebent as shown in FIG. 1, for example. The diameter of at least a portionof each of members 16 and 17 is preferably greater than the diameter ofthe respective flexible members (18 and 19), coupled thereto so that theflexible members can easily be pulled through an opening formed in thetissue (or other material) by the needle. The distal ends of the members16 and 17 are preferably rigid to facilitate penetration of tissue. Theremaining length of members 16 and 17 may be rigid or flexible tofacilitate movement of the needle through the tissue as furtherdescribed below. Tips 30 and/or 31 may have various configurations andmay, for example, be conical, tapered, or grounded to attain a three orfour facet tip. Members 16 and 17 may be made from stainless steel orany other suitable material, such as a polymeric material. It is to beunderstood that members 16 and 17 may have a shape or radius ofcurvature other than the one shown, without departing from the scope ofthe invention. Members 16 and 17 may also be integrally formed with theflexible member 18 (e.g., both piercing member and flexible memberformed of the same material).

The flexible members 18 and 19 may be in the form of a suture formedfrom conventional filament material, metal alloy, such as nitinol,polymeric material, or any other suitable material. The material may benon-stretchable or stretchable, solid or hollow (as shown, for example,in FIGS. 2A and 2B), and have various cross-sectional diameters. Theflexible members or sutures may have a cross-sectional diameter of 0.003inch, and lengths ranging from about 10 mm to about 300 mm, for example.The diameter and length of the suture will vary depending on thespecific application. The sutures may be attached to the piercingmembers 16 and 17, respectively, by crimping or swaging the piercingmember or needle onto the suture, gluing the suture to the piercingmember or needle, or any other suitable attachment method. Flexiblemembers 18 and 19 may have cross-sectional shapes other than the oneshown herein and may have other constructions as well.

Referring to FIG. 2A, an alternate flexible member construction isshown. Flexible member 18′ generally comprises a flexible filament 14,which may be in the form of a metal wire, and tube or sleeve 15 whichmay be in the form of a hollow suture. Tube 15 surrounds filament 14with one end of the filament 14 secured to piercing member 16 and itsother end secured to coupling 28 with glue, for example. The filamentmay provide kink resistance and pull strength (to minimize or eliminatestretch), and is especially advantageous when using very thin materialfor tube 15. Tube 15 may, for example, comprise polymeric materials suchas polyurethane or polyester. It is noted that at least the portions ofthe tube adjacent to needle 16 and coupling 28 have the same diameter asthe portions of the coupling and needle adjacent thereto. Thiseliminates the need for the tapered portions 2 and 3 shown in FIG. 1 orother transition sections to minimize or eliminate the step between theflexible member and needle and/or the flexible member and the coupling.Of course, the diameter of the entire flexible member may be the same asthat of the coupling and the portion of the needle adjacent to theflexible member as indicated in FIG. 2A. It also should be apparent fromthe foregoing that the construction of flexible member 18′ may besubstituted for flexible member 19.

Referring to FIG. 2B, another hollow flexible member construction isshown. Flexible member 18″ comprises tube or sleeve 15, which may be inthe form of a hollow suture. Tube 15 is secured to piercing member orneedle 16 and coupling 28 through posts or anchors 4, which in turn, aresecured to piercing member or needle 16 and coupling 28. The relativedimensions of tube 15 as compared to needle 16 and coupling 28 may bethe same as those describe in connection with FIG. 2A for the samereasons. Further, flexible member 18″ may be substituted for flexiblemember 19 as well.

Referring to FIGS. 3-6, fasteners, which were shown in copending U.S.patent application Ser. Nos. 09/089,884 and 09/090,305 and which may beused in the present invention, first will be described. Referring toFIGS. 3A-C, one embodiment of a fastener (e.g., fastener 20) comprises adeformable wire 34 made of a shape memory alloy. A nickel titanium(nitinol) based alloy may be used, for example. The nitinol may includeadditional elements that affect the yield strength of the material orthe temperature at which particular pseudoelastic or shapetransformation characteristics occur. The transformation temperature maybe defined as the temperature at which a shape memory alloy finishestransforming from martensite to austenite upon heating (i.e., A_(f)temperature). The shape memory alloy preferably exhibits pseudoelastic(e.g., superelastic) behavior when deformed at a temperature slightlyabove its transformation temperature. At least a portion of the shapememory alloy is converted from its austenitic phase to its martensiticphase when the wire is in its deformed configuration. As the stress isremoved, the material undergoes a martensitic to austenitic conversionand springs back to its original undeformed configuration. When the wireis positioned within the tissue in its undeformed configuration, aresidual stress is present to maintain the tissue tightly together (seee.g., FIG. 16F). In order for the pseudoelastic wire 34 to retainsufficient compression force in its undeformed configuration, the wireshould not be stressed past its yield point in its deformedconfiguration to allow complete recovery of the wire to its undeformedconfiguration. The shape memory alloy is preferably selected with atransformation temperature suitable for use with a stopped heartcondition where cold cardioplegia has been injected for temporaryparalysis of the heart tissue (e.g., temperatures as low as 8-10 degreesCelsius).

It is to be understood that the shape memory alloy may also be heatactivated, or a combination of heat activation and pseudoelasticproperties may be used, as is well known by those skilled in the art.

The cross-sectional diameter of wire 34 and length of the wire will varydepending on the specific application. The diameter “d” of wire 34 maybe, for example, between 0.001 and 0.015 inch. For coronary bypassapplications, the diameter is preferably between 0.001 and 0.008 inchwith a diameter “D” of the loop (FIG. 3A) being between 0.0125 and0.0875 inch. As shown in FIGS. 3A and 3B, wire 34 may have a circularcross-sectional shape and a generally ring or loop shaped configurationwhen in a closed position. The diameter “D” of the loop of the fastener20 (with coil 26, which may be platinum) in its closed position ispreferably sized to prevent movement between adjacent tissues. It is tobe understood, however, that the wire may have other cross-sectionalshapes such as rectangular, or may be formed from multiple strandswithout departing from the scope of the invention.

One end of wire 34, which may be referred to as the proximal end of wire34, may include an enlarged portion 36 having a cross-sectional areagreater than the cross-sectional area of the wire to resist the coilfrom passing thereover. The enlarged portion 36 also may be provided tocooperate with a release mechanism as will be discussed in more detailbelow. Enlarged portion 36 may be formed by attaching a member to theend of wire 34 by welding, gluing or other suitable attachment means ormay be formed integrally with the wire by deforming the end of the wire.The other end of wire 34, which may be referred to as the distal end ofwire 34, also may include an enlarged portion 38 for engagement with arestraining device, such as restraining device 24 (see. e.g., FIG. 1),or a locking device or release mechanism, such as release mechanism 28(see e.g., FIG. 1), as further described below. The enlarged portion 38may be formed by deforming the end of the wire 34 by swaging or arcwelding, or attaching an enlarged portion to the end of the wire bywelding, swaging, or other suitable means. Although enlarged portions 36and 38 are shown with spherical and cylindrical configurations, otherconfigurations or configuration combinations can be used. For example,both enlarged portions may be spherical or cylindrical, or portion 36may be cylindrical and portion 38 spherical.

Referring to FIGS. 3A-C, fastener 20 is shown in open and closedconfigurations. When wire 34 is in an undeformed or closedconfiguration, the fastener is closed (as shown in FIGS. 3A and 3B) forkeeping or connecting tissue together, and when wire 34 is in a deformedor open configuration, the fastener is open (as shown in FIG. 3C) forinsertion of the wire into tissue. As discussed above, wire 34 is in itsclosed configuration when in a relaxed state. Wire 34 is preferably notdeformed past its yield point in its open position. Accordingly, it mayhave a U-shaped configuration in its open position to facilitateinsertion of the wire through the tissue. It is to be understood thatU-shaped configuration may be alternatively substituted by an equivalentstructure such as C-shaped, V-shaped, J-shaped, and other similarlyshaped configurations. Wire 34 is moved from its closed position to itsopen position by a restraining device, as further described below. Whenin its closed position, wire 34 forms a loop with the ends of the wirein a generally side-by-side or overlapping orientation (FIG. 3B).

Wire 34 maybe formed in the above-described shape by first wrapping thewire onto a mandrel and heat-treating the wire at approximately 400-500degrees Celsius for approximately 5 to 30 minutes. Wire 34 is then airquenched at room temperature. The mandrel may have a constant diameteror may be conical in shape.

Referring to FIG. 4, an alternate configuration of fastener 20 in itsclosed position is shown, and generally indicated with reference numeral40. Fastener 40 forms a spiral configuration in its closed position fortrapping the tissue within a loop formed by the spiral. In its openposition, the fastener 40 is configured to form less than a full 360degree turn, and may be made to have an open position as shown in FIG.3C, for example.

Referring to FIGS. 5A and 5B, another configuration of fastener 20 isshown in its closed position, and is generally designated with referencenumeral 41. Fastener 41 is formed in a spiral about a centrallongitudinal axis A. As shown in FIG. 5B, fastener 41 has a generallyconical shape along the longitudinal axis A, with a decreasing diameteras the radius of curvature of fastener 41 decreases. Fastener 41 has aninner end portion 45 and an outer end portion 47, with the enlargedportion 38 of the wire being disposed at the outer end portion forengagement with the restraining device 24 as shown, for example, in FIG.3C. Referring to FIG. 6, a modification of fastener 41 is shown, andgenerally indicated with reference numeral 43. Fastener 43 is similar tofastener 41 described above, except that enlarged portion 38, which isadapted for engaging a restraining device or releasable lockingmechanism, is positioned at the inner end portion 45 of the fastener.Placement of restraining device 24 at the inner end portion 45 offastener 43 increases the compression force of the wire in itsundeformed position on the tissue and decreases the surface area of thefastener exposed to blood flow.

It is to be understood that the fasteners may have undeformed ordeformed configurations different than those shown herein withoutdeparting from the scope of the invention. In addition, a locking clip(not shown) may also be attached to connect the ends of the fastener(such as fastener 20, 40, 41, 43) when the fastener is in its closedposition to prevent possible opening of the fastener over time. Thelocking clip may also be integrally formed with one end of the fastener.

As shown in FIG. 3C, wire 34 is surrounded by spring or coil 26 that,along with the locking device 28, restrains the wire in its deformedconfiguration. Coil 26 comprises a helical wire forming a plurality ofloops that define a longitudinal opening 44 for receiving the shapememory alloy wire 34. Coil 26 may be formed from a platinum alloy wirehaving a cross-sectional diameter of approximately 0.0005-0.005 inch,for example. The helical wire may have other cross-sectional shapes andbe formed of different materials. Coil 26 is preferably sized so thatwhen in its free (uncompressed state) it extends the length of wire 34with one end adjacent the enlarged portion 36 at the proximal end of thewire and the other end adjacent enlarged portion 38 at the distal end ofthe wire. It is to be understood that the coil may not extend the fulllength of the wire. For example, a flange or similar device may beprovided on an intermediate portion of wire 34 to limit movement of thecoil along the length of the wire.

When coil 26 is in its free state (with the wire in its undeformedconfiguration), loops of the coil are generally spaced from one anotherand do not exert any significant force on the wire 34 (FIGS. 3A and 3B).When the coil 26 is compressed (with the wire 34 in its deformedconfiguration), loops of the coil on the inner portion 46 of the coilare squeezed together with a tight pitch so that the loops arecontiguous with one another while loops on the outer portion 48 of thecoil are spaced from one another (FIG. 3C). This is due to thecompressed inner arc length of coil 26 and the expanded outer arc lengthof the coil. The compression of the loops on the inner portion 46 ofcoil 26 exerts a force on the inner side of wire 34 which forces thewire to spread open (i.e., tends to straighten the wire from its closedconfiguration to its open configuration). The end of coil 26 adjacentenlarged portion 36 is held in a fixed position relative to wire 34. Theopposite end of coil 26 is free to move along wire 34 and is held inplace when the coil is in its compressed position by locking device 28.It should be understood, however, that a coil (not shown) havingsufficient stiffness, for example, might be used where adjacent loops donot contact one another when the coil is compressed to force wire 34into an open position.

Referring to FIGS. 7A-7C, one embodiment of a releasable locking deviceor release mechanism, which is disclosed in U.S. patent application Ser.Nos. 09/089,884 and 09/090,305, is shown. Releasable locking device 28 ais adapted for releasably coupling a fastener (such as any of thefasteners shown in FIGS. 3-6) to a flexible member (such as flexiblemember 18, 18′ or 18″) is shown and generally designated with referencenumeral 28 a. Release mechanism 28 a comprises a flexible tubular member50 having a distal end portion 52 and is shown with tapered section orsleeve 2, which in turn is coupled to the flexible member. Taperedsection or sleeve 2, which provides a transition between the flexiblemember and fastener for insertion of the fastener through tissue, may bea separate member coupled to tubular member 50 or be formed integrallytherewith. Tubular member 50 further includes a proximal end portion 54releasably attached to wire 34. In this manner, release mechanism 28areleasably couples the flexible member and needle to the surgicalfastener such as fastener 20. In addition to releasably coupling theflexible member and needle to the fastener, the locking device orrelease mechanism compresses coil 26 to bias the fastener or surgicalclip 20 in its open configuration, facilitating insertion of the lockingdevice 28 through tissue. Although a straight tapered section is shown,it may be curved as well. Tapered portion 2 may be formed from a metalalloy such as stainless steel or a suitable polymeric material and maybe solid or in the form of a sleeve as noted above. Generally, taperedsection 2 gradually diminishes in diameter to provide a smooth,non-stepped transition between the relatively small diameter of theflexible member to the larger diameter of locking device such as lockingdevice 28 a. The flexible member such as flexible member 18 may beswaged into the tapered section, or a heat shrink plastic covering mayhold the flexible member in place. The locking device may also becurved.

Tubular member 50 is movable between a locked position (FIGS. 7A and 7B)for holding coil 26 in its compressed position and wire 34 in itsdeformed position, and an unlocked position (FIG. 7C) for inserting orreleasing the wire and coil. Referring to FIGS. 7B and 7C, three slots58 are shown formed in tubular member 50 extending from the proximal end54 of the member and along at least a portion of the member. Slots 58are provided to allow the proximal end 54 of tubular member 50 to openfor insertion and removal of the wire 34. It is to be understood thatthe number of slots 58 and configuration of the slots may vary, ortubular member 50 may be formed to allow expansion of proximal end 54without the use of slots.

Proximal end 54 of tubular member 50 includes a bore 62 having adiameter slightly greater than the outer diameter “d” of wire 34, butsmaller than the diameter of enlarged portion 38 at the distal end ofthe wire and the outer diameter of the coil 26. Bore 62 extends into acavity 64 sized for receiving the enlarged portion 38 of wire 34.Tubular member 50 may be described as having an annular flange 61 forreleasably securing enlarged portion 38. As shown in FIG. 7C, uponapplication of an inwardly directed radial squeezing force on thetubular member 50 proximal end 54 of the tubular member is opened toallow for insertion or removal of wire 34. When the force is released,the tubular member 50 moves back to its locked position and securelyholds wire 34 in place and compresses the coil 26 as shown in FIG. 7A. Adisc 51 may be inserted into tubular member 50 to act as a fulcrum andcause the proximal end 54 of the tubular member to open. Alternatively,disc 51 may be integrally formed with tubular member 50. As shown inFIG. 7A, the length l of the bore 62 or flange 61 determines the amountof compression of the coil, which in turn determines the amount ofdeformation of wire 34. The greater the length l of bore 62, the greaterthe compression of coil 26 and the more straightening of wire 34 willundergo. The compression of coil 26 is preferably limited so that wire34 is not stressed beyond its yield point. This allows wire 34 to revertback to its original undeformed configuration and apply sufficientpressure to hold the connected tissue together.

FIGS. 8A, 8B and 8C illustrate another release mechanism which isgenerally designated with reference numeral 28 b. FIGS. 8A and 8B showthe release mechanism in a locked position, and FIG. 8C shows therelease mechanism in an unlocked position. Release mechanism 28 bcomprises a tubular member 80, which has proximal and distal ends 88 and89, respectively. Tubular member 80 further includes bore 82 formedtherein and a cavity or recess 84 extending radially outward from bore82 into the tubular member. Recess 84 is configured to receive enlargedportion 38 or wire 34 as best illustrated in FIG. 8A. Recess 84 and bore82 form an annular flange 86, which has an inner diameter less than thatof enlarged portion 38 and, thus, resists removal of the enlargedportion. In the embodiment shown in FIG. 8A-C, three slots 87 are formedin tubular member 80 as in the embodiment shown in FIGS. 7A-C. The slotsextend longitudinally from the proximal end 88 of tubular member 80 andform fingers 81, which radially expand and release wire 34 upon radialcompression of the tubular member as shown in FIG. 8C and as describedabove in connection with release mechanism 28 a. In this embodiment,however, enlarged portion 38 forms a fulcrum. Although threeequiangularly spaced slots, which extend parallel to the longitudinalaxis are shown as in release mechanism 28 a, the number andconfiguration of the slots may vary, or the tubular member may be formedto allow expansion of the proximal end portion without the use of slots.A tapered section 2 also may be provided as described above inconnection with release mechanism 28 a.

FIGS. 9A-9E illustrate yet another release mechanism which is disclosedin U.S. patent application Ser. No. 09/259,705, filed on Mar. 1, 1999and entitled Tissue Connector Apparatus With Cable Release. The releasemechanism is generally indicated with reference numeral 28 c in FIGS.9A-9E where FIGS. 9A-C show the mechanism coupled with a fastener, andFIGS. 9D and 9E show the release mechanism depressed for release of thefastener. Locking device or release mechanism 28 c comprises a pluralityof substantially rigid strands, preferably wires 106, arrangedsubstantially parallel to one another and circularly about alongitudinal axis of the aligned strands, to form a tube-likeconfiguration, as can be seen in the cross-sectional view of FIG. 9C andthe perspective view in FIG. 9A. Alternatively, strands 106 may becables or some other substantially rigid strand elements arranged in thesame manner as the wires shown in FIG. 9C. Upon arrangement into thecircular configuration, the hidden end portions 106 a of the strands arecoupled to tapered section 2, which is coupled to a piercing member orneedle through a flexible member such as flexible member 18.

Preferably, a rod 162 extends from tapered section 2 to facilitatefixation of the strands thereto. The coupling of the strands to taperedsection 2 is preferably accomplished by gluing or soldering to rod 162,although other equivalent or similar known joining techniques may beemployed (e.g. welding, threadably attaching, etc). Similarly, rod 162is preferably glued, soldered or threaded into the needle or transitionelement. In an alternate arrangement, the flexible member may extendthrough tapered section 2 and form a substitute structure for rod 162.This may be preferred when the flexible member is a metal wire.

The end portions 106 b of the strands in the vicinity of the fastenerstrands include notches 109 which are formed into the strands to a depthequal to approximately half the diameter of the strand 106. When thestrands are arranged in the circular configuration described above, thenotches 109 form a chamber 108 configured for receiving and holdingenlarged portion 38. Although enlarged portion 38 is shown as having aspherical shape, it may have other shapes including a barrel shape, orother shape that may be easily grasped and easily released. The notchesare preferably placed about 0.015″ from the free ends of the strands,but this distance, of course, can be modified, depending upon the amountof compression of spring 26 that is desired when ball 38 is insertedinto and held by notches 109.

After placement of ball 38 within chamber 108 formed by notches 109, ashrink wrap layer, preferably a shrink tubing 110 may be provided overat least free end portions 106 b of wires or strands 106, and the tubingheated to compress against strands 106 and hold them in place againstball 38, preferably symmetrically against ball 38. Together, tubing 110and strands 106 effectively hold ball 38 captive within notches 109.Alternatively, other plastic or elastic restraining members may bemounted around the distal portions of the wires or strands to aid inmaintaining them in place, preferably symmetrically against ball 38.Still further, strand members may be designed with an elastic springforce sufficient to maintain notches 109 in place with sufficient forceto maintain the bail 38 captive therein under the tensile forcesnormally experienced during a suturing procedure. Although aseven-strand embodiment is shown, it should be understood that fewer ormore than seven strands may be used. The number of strands may varydepending on, for example, the size of the clip or the size of thestrands. Typically, the number of strands may range from two to ten. Ina coronary anastomosis, the number of strands preferably will range fromfive to seven although other numbers may be used.

In assembling, enlarged portion 38 of wire 34 is placed in chamber 108.Tubing 110 is wrapped around at least a portion of the strands (as shownin the drawings) and heated to maintain enlarged portion 38 captivewithin the cavity formed by the strands. Compression coil or spring 26is slid over wire 34 and compressed against portions 106 b such that thefastener is in its open configuration. Enlarged portion 36 may then beformed or attached to wire 34 to maintain the fastener in its openconfiguration.

Release mechanism 28 c is movable between a locked position (FIGS. 9A-9c) and an unlocked position (FIGS. 9E and 9F). In the locked positionthe ball 38 is held within notches 109 and consequently, coil 26 is heldin its compressed position, thereby maintaining fastener wire 34 in itsdeformed or open position. In the unlocked position, ball 38 is releasedfrom the notches, thereby allowing the coil 26 to expand, which causesthe fastener wire 34 to close. The closure conformation of the wire maybe characterized by any of those described above with reference to FIGS.3-6, for example.

Movement of the release mechanism to the open position is accomplishedby applying a compressive force to the shrink tube 110 and bundle ofstrands 106, as shown in FIGS. 9D and 9E. Advantageously, thecompressive force may be applied at any opposing locations around thecircumference of the shrink tube as long as the implement applying theforce is oriented at an angle to the strands, preferably substantiallyperpendicular thereto, to allow the implement to traverse the strands soas to deform the positions thereof when the force is applied. Forexample, needle holder 111 could be rotated 90° (or virtually any otherangle) with respect to the strands 106 as shown in the plane of thedrawing, while retaining the capability of deforming the strands to anopen position upon application of a compressive force. The compressiveforce is preferably applied using a standard needle holder 111 orforceps, although other tools could be used, preferably those withapplicators narrower than the length of the shrink tube 110. As shown,the strands or wires 106 get distorted from their circular configurationunder the compression. This change in shape stretches the shrink tube110 from a circular configuration to a somewhat ellipticalconfiguration, and removes some of the notches 109 from contact withball 38, thereby permitting removal of ball 38 from within the chamberpreviously formed by notches 109 in the closed position.

Referring to FIG. 9F, release mechanism 23 c also may be used toreleasably couple the other end of the fastener to another flexiblemember such as flexible member 19, which in turn, is coupled to a needlesuch as needle 17 as shown in FIG. 1. In this arrangement, a member orstopper 115, which may be annular, is secured to the other end of thefastener or wire 34 to prevent enlarged portion 36 from passing throughthe compression spring upon release from release mechanism 23 c. Otherrelease mechanisms, which provide synchronized release of both needlesillustrated in FIG. 1, also can be used.

FIGS. 10A-10F illustrate synchronized fastener release systems.Referring to FIGS. 10A-10C, a first synchronized release system is shownin a coupled and decoupled state, respectfully. Although one releasemechanism is shown as corresponding to release mechanism 28c, releasemechanisms 28 a or 28 b or any release mechanism which releasablycouples the flexible member or needle to the surgical fastener andeffects compression of coil 26 also may be used. At the other end of thefastener or wire 34, a release mechanism that responds to thecompressive state of coil 26 and releases the fastener or wire 34 uponrelease of compressive forces on the coil is shown and generallydesignated with reference numeral 29 a. Release mechanism 29 a comprisestwo members 121 each having a recess 122 formed therein and arranged toform chamber 124 when members 121 are aligned as shown in FIG. 10A.Recesses 122 are configured to retain enlarged portion 36, which isshown with a cylindrical configuration, but may have a spherical orother suitable shape for operatively associating with a suitablyconfigured chamber. Further, members 121 may have semicirculartransverse cross sections or some other combination of transverse shapesthat can collectively provide the desired chamber to retain enlargedportion 36. The number of members 121 also may vary as would be apparentto one of ordinary skill.

Release mechanism members 121 have tapered ends 126, which areconfigured for positioning between coil 26 and fastener wire 34 as shownin FIG. 10A. When tapered ends 126 are so positioned and coil 26 is in acompressed state, coil 26 holds tapered ends 126, which are normallybiased away from each other as shown in FIG. 10C, sufficiently togetherto retain enlarged portion 36 within chamber 124. When release mechanism28 c is actuated (e.g., radially compressed) to release enlarged portion38 of fastener wire 34, coil 26 assumes its relaxed state, therebyreleasing tapered ends 126 of release mechanism 29 a from the coil andallowing the tapered ends to radially expand and release enlargedportion 36 of fastener wire 34 as shown in FIG. 10C. Accordingly, bothneedles and flexible members may be decoupled from the fastener whenrelease mechanism 28 c is actuated.

FIGS. 10D-10F show another synchronized fastener system that is the sameas the system shown in FIGS. 10A-10C with the exception of releasemechanism 29 b and the cooperating portion of the fastener or wire 34being substituted for release mechanism 29 a. In this embodiment, anannular member or stopper 115, which may be annular, is slidably coupledto fastener wire 34. Member 115 is configured to resist passage of coil26 thereover. Accordingly, member 115 may have an outer diameterslightly greater than at least the portion of the coil adjacent thereto.A tapered or frustoconical member 3′ is secured to an end of fastenerwire 34, which need not include an enlarged portion. Member 3′ is thesame as member 3 with the exception that member 3′ has a channel 134 forreceiving flexible member or suture 19. Channel 134 extends radiallyoutward from bore 132, which is formed through member 3′, for receivingthe fastener or wire 34.

Flexible member 19 is threaded through channel 134 and between taperedmember 3′ and annular member 115. When coil 26 is in a compressed stateas shown in FIG. 10D, the coil urges member 115 toward tapered member 3′and compresses flexible member 19 therebetween. In this manner, flexiblemember 19 is secured to the fastener or wire 34. When release mechanism28 c is actuated (e.g., radially compressed) to release enlarged portion38 of the fastener or wire 34, coil 26 assumes its relaxed state so thatannular member 155 may slide away from tapered member 3′ and releaseflexible member 19. Accordingly, both needles and flexible members maybe removed from the fastener when release mechanism 28 c is actuated.Although a metal flexible member may be used, a polymeric flexiblemember may be preferred.

FIGS. 11A and 11B show another release mechanism generally indicatedwith reference numeral 29 c. Release mechanism 29 c includes a sleeve142, which is slidably mounted over flexible member 19 so that it can bepositioned over the flexible member and the fastener or wire toreleasably hold the flexible member and the fastener together. The endportion of the flexible member opposite the needle and the end portionof the fastener or wire to be engaged therewith may be configured toprovide interlocking engagement therebetween. In the embodiment shown inFIGS. 11A and 11B, the flexible member, which preferably is metal inthis example, and the fastener or wire end portions have mating flangeand groove configurations. Flexible member 19 includes groove 144 a andflange 146 a, which mate with or interlockingly engage groove 144 b andflange 146 b, which are formed in wire 34. When sleeve 142 is moved awayfrom the fastener or wire, the coupling becomes unrestrained and theflexible member and the fastener or wire can be readily separated byremoving flanges 146 a and 146 b from grooves 144 a and 144 b as shownin FIG. 11B. Member 115 may be secured to fastener wire 34 to preventthe end of coil 26 adjacent to groove 144 b and flange 146b from slidingthereover. Member 115 also may be described as a stopper for spring 26.

FIGS. 12A and 1213 show another release mechanism, which is generallydesignated with reference numeral 29 d. In this embodiment, taperedmember 3 is provided with a bore for receiving both flexible member 19and the fastener or wire 34. Member or collar 115 may be fixedly securedto the fastener or wire 34 to resist coil movement over the wire andtoward the flexible member. The fastener or wire also may be fixedlysecured to the inner wall of tapered member 3 by, for example, gluing orwelding. One end of the flexible member is tied into a knot such as knot150. The knot is packed into the bore 152 and the tapered member isswaged or crimped as shown in FIGS. 12A and 12B to secure the knot inthe bore. The flexible member is cut as shown in FIG. 12B to decouplethe flexible member from the fastener.

FIGS. 13A and 13B illustrate a further release mechanism, which isgenerally designated with reference numeral 29 e. Release mechanism 29 egenerally comprises a release member having a cavity formed therein toreceive the fastener or wire 34 and a portion configured for severingthe fastener wire. This advantageously eliminates the need for aseparate cutting tool to separate the suture or needle from thefastener. One example of such a release member is shown as releasemember 160. Release member 160 has one end that is fixedly secured totapered member 3 to which flexible member 19 is secured. Alternatively,members 3 and 160 may be integrally formed. Release member 160 isconfigured to form a cavity 162 therein and may be in the form of asleeve. Member 160 includes annular flange 164 through which fastenerwire 34 is received. Annular flange 164 includes an annular lip 166,which forms a cutting surface or annular blade. Release member 160 alsomay include an opening for receiving flexible member 19 therethrough asshown in FIGS. 13A and 13B. In this example, release member 160 can befixedly secured to flexible member 19, which, in turn, can be fixedlysecured to tapered member 3. Of course, it should be understood thatmembers 160 and 3 can be directly secured to one another or integrallyformed as a single piece. When release member 160 is radially compressedas shown in FIG. 13B, annular lip severs fastener wire 34 and decouplesflexible member therefrom. Fastener wire 34 may be provided with annulargroove 168 to enhance wire fracture. Release member 160 or annular lip166 may be 400 series stainless steel or tool steel to facilitatehardening. Other materials that tend to provide an effective cuttingtool also may be used. Release member 160, however, should comprisematerial that provides the desired flexibility. Further, it should beunderstood that although release member 160 is shown with a generallycylindrical configuration, other configurations may be used. Inassembly, member 115, which may be annular, may be swaged, glued orwelded to wire 34 to compress coil 34 after the other end of wire hasbeen secured to a locking device or coupling so that the fastener opensas may be done in the embodiments of FIGS. 11A and B and 12A and B. Wire34 may be preformed with groove 168 or the groove formed prior tosliding member 160 over wire 34 so as to engage blade 166 with thegroove.

It is to be understood that locking devices other than those describedabove may be used without departing from the scope of the invention. Forexample, a locking device (not shown) may comprise a tubular memberhaving an opening formed in a sidewall thereof for receiving an endportion of the wire. The end of the wire may be bent so that it isbiased to fit within the opening in the sidewall of the tubular member.An instrument, such as a needle holder may then be used to push the wireaway from the opening in the tubular member and release the wire fromthe tubular member. Various other types of locking devices including aspring detent or bayonet type of device may also be used. Further, thefastener or wire end portions may be configured differently than thatshown. For example, one or both of the fastener or wire end portions maybe provided with grooves instead of enlarged portions and the releasemechanisms or locking device arms, such as, for example, fingers 81 orstrands 106, may be provided with projections to releasably engage withthe grooves.

FIG. 14A is a front view of another embodiment of a tissue connectorassembly of the present invention which is generally designated withreference numeral 211. Tissue connector assembly 211 is the same astissue connector assembly 11 with the exception that locking device orrelease mechanism 28 is directly connected to needle 16. Although any ofthe release mechanisms 28 a-c may be used to couple the fastener toneedle 16; release mechanism 28 c is shown in FIG. 14B for purposes ofillustrating a connection between a locking device and needle 16.

Referring to FIG. 14B, rod 162 extends from needle 16. Rod 162 andneedle 16 may be integrally formed or be separate elements secured whichare fixed to one another. The coupling of strands 106 to the needle ispreferably accomplished by gluing or soldering to the rod 162, althoughother equivalent or similar known joining techniques may be employed(e.g. welding, threadably attaching, etc). Similarly, when the rod andneedle are discrete elements, the rod is preferably glued, soldered orthreaded into the needle. Alternately, rod 162 may extend from or beaffixed to a transition element that in turn is affixed to needle 16.

FIG. 15 is a front view of a lateral tissue connector which is generallydesignated with reference numeral 300 and which can be used inconjunction with any of the assemblies described above as will bedescribed in detail below. Tissue connector assembly 300 generallyincludes needle 16, a locking device or release mechanism, and afastener, which may be fastener 20, 40, 41, or 43, for example. In thisembodiment, needle 16 is attached directly to a locking device, such aslocking device 28c, a connection for which is described above withreference to FIG. 14A. FIG. 14A shows tissue connector assembly 211 withthe fastener in its open (deformed) configuration.

FIG. 17 is a front view of a bridge clip embodiment of a tissueconnector assembly of the present invention, generally designated withreference numeral 1701. Tissue connector assembly 1701 includes a bridgeclip 1707 having a pair of clips or fasteners 1703 and a connectingbridge 1705. Each of the pair of clip and components corresponding toeach of the pair of clips is denoted with a prime or double-prime. Thus,for example, the pair of clips includes a first clip 1703′ and a secondclip 1703″. In one embodiment, the materials and configuration of tissueconnector assembly 1701 are essentially symmetric, and correspondingprimed and double-primed components are mirror images of one another. Inanother embodiment, tissue connector assembly is not symmetric, and thusa primed component and the corresponding double-primed component may beof different materials or geometry, or may be constructed differentlybut be functionally equivalent.

Each one of clips 1703 includes wire 34 surrounded by a correspondingcoil 26, that can provide a bias force to keep each clip in an openconfiguration. Clips 1703 may be fastener 20, 40, 41, 43, or othersimilar fasteners. The end portion of each coil 26 near bridge 1705 isrestrained by a corresponding stopper 115 attached to wire 34, while theopposite end of the coil can be restrained by a corresponding releasemechanism 28. As with the embodiment of FIG. 1, the free ends offasteners 1703 are releasably coupled through the release mechanisms 28to flexible members 18, and to piercing members 16, respectively. Thetwo clips 1703 are thus seen to act as two clips similar to fastener 20of FIG. 1, joined together near their respective stoppers 115. In thepreferred embodiment, wires 34′ and 34″ are two sections of a singlewire 34 that is made of a shape memory alloy that has be heat treated toform the double-loop configuration described herein. The bridge clip1707 can be assembled by heat treating wire 34 to the closedconfiguration, as describe previously, threading stoppers 115 followedby coils 36 over wires 34, mounting the release mechanisms 28, movingstoppers 115′ and 115″ apart to produce the required biasing force onthe wire, and then crimp, swage or weld the stoppers to the wire. Anassembly 1701 thus assembled will maintain the configuration of FIG. 17until the biasing force of one of coils 26 is released.

For a symmetric tissue connector assembly 1701 embodiment noted in theprevious embodiment, each of clips 1703 are constructed of the samematerials, with clip 1703′ and clip 1703″ being mirror images. Examplesof tissue connector assembly 1701 that is not symmetric, include, butare not limited to having clips 1703′ and 1703″ of different sizes orshapes, having coils 26′ and 26″ produce different biasing forces, orhaving flexible members 18 of different lengths, sizes or materials.

FIG. 18 shows the configuration of the bridge clip 1707 of FIG. 17 afteractuation of release mechanisms 28. Upon release of release mechanisms28, coils 26 move towards enlarged portions 36, reducing the biasingforce and allowing clips 1703 to move towards the closed configuration,as shown. Thus in addition to causing the release of bridge clip 1707from flexible members 18, actuation of release mechanisms 28 alsotriggers a self-closing action causing the clip to transition from theopen configuration of FIG. 17 towards the closed configuration of FIG.18. The separation and orientation of clips 1703′ and 1703″ are fixed bythe heat-treated configuration of the wire. Thus in one use, bridge clip1707 can be used to secure tissue at two positions (through the loops ofclips 1703′ and 1703″) that are accurately determined by the separationprovided by bridge 1705.

As an alternative embodiment, coils 26′ and 26″ can be replaced with onecoil (not shown) that is coupled to both release mechanisms 28, andwhich supplies a biasing force to keep both of clips 1703 biased in anopen position. Release of either of either of release mechanisms 28′ or28″ partially releases the biasing force, causing both clips 1703 toreturn to a partially closed position. Release of the other of releasemechanism 28 decreases the biasing force to allow both of clips 1703 toreturn to a fully closed position. There are many alternativeembodiments for the various components of tissue connector assembly1701. Thus for example, flexible members 18 can be constructed as shownin one of FIG. 2A or 2B or other structures as described previously.Additionally, the discussion of release mechanisms described inreference to FIGS. 7 through 11 can also be applied, separately or incombination to the two release mechanisms 28 of tissue connectorassembly 1701.

The shape of bridge clip 1707 when released from flexible members 18 isshown in FIG. 18. With release mechanisms 28 of FIG. 17 released, bothself-closing fasteners 1703 become unbiased and assume the closedconfigurations of FIG. 18. In the closed configuration the bridge 1705is clearly seen to be a nearly straight portion that is formed betweenthe two closed clips 1703. In a specific embodiment, fasteners 1703 areformed of a memory shape alloy. By forming the clip material in theshape shown in FIG. 18, the two fasteners 1703 are connected by a fairlyrigid bridge portion 1705. One particularly useful embodiment orientsloop of clips 1703 at right angles to bridge 1705. It can be seen in thefigure, and by subsequent descriptions, that the closed fastener of FIG.18 can be used to hold tissue at two positions (one at by each cliploop) separated by the distance of the bridge 1705. The bridge clip 1707thus can be used to secure tissue at two locations with the loops offasteners 1703, with the locations supported by the bridge 1705. Bridgeclip 1.707 can thus be used to hold tissues together at two separatelocations, or by application of pressure by bridge 1705 onto fasteners1703, pressure may be applied along the length of the bridge clip.Specific uses of bridge clip 1707 include, but are not limited to,providing anchoring of the fastener against the tissue, and as such areuseful in many of the attachment procedures described previously, andattaching tissues as for example, as a type of horizontal mattresssuture.

As noted above, tissue connector assemblies described above have manyuses. They may be especially useful for minimally invasive surgicalprocedures including creating an anastomosis between a vascular graft 12and an artery 14. The anastomosis may be used to replace or bypass adiseased, occluded or injured artery. A coronary bypass graft procedurerequires that a source of arterial blood flow be prepared for subsequentbypass connection to a diseased artery. An arterial graft may be used toprovide a source of blood flow, or a free graft may be used andconnected at the proximal end to a source of blood flow. Preferably, thesource of blood flow is one of any number of existing arteries that maybe dissected in preparation for the bypass graft procedure. In manyinstances it is preferred to use the left internal mammary artery (LIMA)or the right internal mammary artery (RIMA), for example. Other vesselswhich may be used include the saphenous vein, gastroepiploic artery inthe abdomen, radial artery, and other arteries harvested from thepatient's body as well as synthetic graft materials, such as DACRON®(polyester fibers) or GORETEX® (expanded polytetrafluoroethylene). If afree graft vessel is used, the upstream end of the dissected vessel,which is the arterial blood source, will be secured to the aorta toprovide the desired bypass blood flow, as is well known by those skilledin the art. The downstream end of the graft vessel is trimmed forattachment to an artery, such as the left anterior descending coronary(LAD). It is to be understood that the anastomosis may be formed inother vessels or tissue.

FIGS. 16A-16D diagrammatically illustrate a method of aligning andconnecting graft and target vessels, such as connecting a graft vessel12 to an artery 14 (target vessel) using tissue connector assemblies 11and 300. In this example, two tissue connector assemblies 11 are used tomake connections at generally opposite sides of the graft vessel andtissue connector assemblies 300 are used to make connections betweenthose made with assemblies 11. The procedure may be accomplished with abeating heart procedure with the use of a heart stabilizer to keep theheart stable, for example. The procedure may also be performedendoscopically. It also should be understood that tissue connectorassemblies 211 may be substituted for assemblies 11.

The patient is first prepped for standard cardiac surgery. Afterexposure and control of artery 14, occlusion and reperfusion may beperformed as required, an arteriotomy is performed on artery 14 toprovide an opening 120 for receiving a graft vessel. After the snaredgraft vessel 12 has been prepared as would be apparent to one ofordinary skill in the art, a tissue connector assembly 11 is attached tothe free end of the graft vessel along an edge margin of the vessel. Inorder to attach the connector assembly 11, the surgeon grasps needle 16with a needle holder (e.g., surgical pliers, forceps, or any othersuitable instrument) and inserts needle 16 into the tissue of graftvessel 12 in a direction from the interior of the vessel to the exteriorof the vessel. The surgeon then releases the needle 16 and grasps aforward end of the needle which is now located outside graft vessel 12and pulls the needle and a portion of suture 18 through the vessel.Needle 17 is passed through opening 120 formed in the sidewall of theartery 14 and inserted into the tissue of the artery in a direction fromthe interior of the artery to the exterior of the artery. The surgeonthen grasps needle 17 located outside the artery 14 and pulls the needleand a portion of suture 19 through the arterial wall. A second tissueconnector assembly 11 may be inserted as described above at a locationgenerally 180 degrees from the location of the first tissue connector ina conventional “heel and toe” arrangement.

Once the tissue connector assemblies 11 are inserted, graft vessel 12 ispositioned above and aligned with opening 120 in the sidewall of theartery 14 (FIG. 16A). A section of each assembly is located betweengraft vessel 12 and artery 14. The needles 16 and 17 arc pulledgenerally away from the artery 14 to reduce the length of the sutures 18and 19 (eliminate slack of the sutures) between vessel 12 and artery and“parachute” the vessel onto the artery (FIG. 16B). The needles 17 arethen pulled away from the artery 14 until each fastener 20 is positionedwithin the target vessel 14 as shown in FIG. 16B. Needles 16 are thenpulled away from graft 12 until the fasteners are positioned with oneend of each fastener 20 extending from the vessel and the opposite endof each fastener extending from the artery (FIG. 16C). The edges of thegraft vessel 12 and artery 14 are positioned adjacent one another toform a continuous interior and exterior surface along the matingportions of the vessel and artery. As shown in FIG. 16F, the tissue iscompressed within the fastener 20.

A surgical instrument (e.g., needle holder) is used to radially squeezeeach locking device 28 to release the locking device from the fastener20. Upon removal of each locking device 28, each coil 26 moves to itsfree uncompressed state which allows fastener wire 34 to return to itsoriginal undeformed closed position (FIG. 16D). As the wires 34 move totheir closed position the adjacent tissues of the graft vessel 12 andartery 14 which were previously pulled together during the parachutingof the graft vessel onto the artery, are squeezed together to securelyengage the graft vessel and artery (FIGS. 16E and 16F). It should benoted that as each locking device 28 is squeezed at least two steps areaccomplished. The fastener 20 is released from locking device 28, thusallowing coil 26 to uncompress and the wire 34 to move to its closedconfiguration, and the needle 16 is released from the fastener. Thus,any of the locking devices 28 described above provides for simultaneousactuating closure of the fastener 20 and release of the needle 16 fromthe fastener. Further, radially compression of release mechanisms 29releases needles 17 and sutures 19 from the fasteners. However, if oneof the synchronous release systems described with reference to FIGS.10A-10F is used, radial compression of a locking device 28 device willeffect essentially simultaneous closure actuation of a respectivefastener and release of needles 16 and 17 and sutures 18 and 19.

The tissue connector assemblies 300 arc subsequently inserted atcircumferentially spaced locations around the periphery of the graftvessel to sealingly fasten graft vessel 12 to artery 14. Needle 16 offastener 300 is inserted into graft vessel 12 from the exterior surfaceof the graft vessel and pushed through the graft vessel and artery 14tissue. The needle holder is then used to pull the needle 16 through thearterial wall. An instrument (same needle holder or other suitableinstrument) is used to apply a squeezing force to the locking device 28to release fastener 20 from needle 16. This allows coil 26 to move toits uncompressed configuration and the wire to move to its closedposition. It should be noted that the tissue connector assemblies 11 mayremain with their fasteners in their open position while tissueconnector assemblies 300 are inserted into the tissue and moved to theirclosed position. The locking devices 28 of the tissue connectorassemblies 11 may subsequently be removed from the fasteners 20 to allowthe fasteners to move to their closed position. The number andcombination of tissue connector assemblies 11 and 300 required tosealingly secure the connecting tissues together may vary. For example,only tissue connector assemblies 11 may be used to complete the entireanastomosis.

Although coils 26 are shown remaining on the fastener or wire (FIG.16D), it is to be understood that coils 26 may also be removed fromwires 34, leaving only the wires in the connected tissue.

As an alternative to inserting tissue connector assemblies. 11 at “heeland toe” locations described above, a number of tissue connectorassemblies 11 may be inserted generally around the location of the heel.The graft vessel may then be pulled towards the artery to determinewhether the opening formed in the sidewall of the artery is large enoughbefore completing the anastomosis. It also should be understood thattissue connector assemblies 211 may be used instead of or in conjunctionwith assemblies 11.

FIGS. 19A-19D diagrammatically illustrate an alternative method ofaligning and connecting graft and target vessels, such as connecting agraft vessel 1901 to an artery 1903 (target vessel) using tissueconnector assemblies 1701 and 1907. The bridge clip of tissue connectorassembly 1701 can be used to secure the anastomosis at the heal or atthe toe, while tissue connector assembly 1907 can be a tissue connectorassembly attached to one piercing member, as disclosed in the copendingU.S. patent application having Ser. No. 09/259,705. Alternatively tissueconnector 300 could be used in place of tissue connector 1907. In thisexample, one tissue connector assembly 1701 is used to make a connectionwhere a toe 1905 of graft vessel 1901 attaches to target vessel 1903,and other tissue connectors 1907 are used at the other attachmentlocations.

FIG. 19A shows tissue connector 1905 after threading each of piercingmembers 16′ and 16″ through the outer surface of toe 1905 and throughthe inner surface of target vessel 1903. Piercing toe 1905 at two pointshaving the approximate spacing of the length of bridge 1705 allows thebridge to be brought against the outer surface of the graft vessel 1901.This positioning, in which one vessel is brought down or “parachuted”onto another, is advantageous for performing an anastomosis, as itallows the graft vessel to be pulled down onto the target vessel 1903.Because the bridge is rigid, the force on target vessel 1903 isdistributed across the bridge 1705. In contrast, the use of a flexiblesuture for this procedure would pull the tissue between the twopiercings together producing a “purse string” effect that is not desiredwhen suturing, and could also possibly tear the tissue.

The piercings on target vessel 1903 are spaced similarly to those on toe1905. With tissue connector 1701 positioned as in FIG. 19A, the piercingmembers 16′ and 16″ can be gently pulled, allowing for precise andcareful placement of toe 1905 on target vessel 1903. Once the vessels1901 and 1903 are aligned and the release members 28 and 29 are pulledthrough the top side of target vessel 1903, bridge clip 1707 can bereleased from the flexible members 18 and piercing members 16. FIG. 19Bshows bridge clip 1707 in the closed configuration as it appears afterjoining vessels 1901 and 1903. Each fastener 1703 a and 1703 b ispositioned, prior to closing, from the outer to inner surface of graftvessel 1901 and through the inner to outer surface of target vessel1903. Upon closing, each fastener completes the loop, holding the twovessels at two positions separated by the distance of the bridge 1705.The fastening of the vessels at two locations that are held together bythe bridge portion provides added support to the anastomosis at thepoint where the forces which tend to pull the vessels apart is greatest.Once the graft-target attachment is secured at toe 1905 the remainder ofthe attachment can be performed using tissue connectors 1907 as shown inFIGS. 19B-C.

Although the suturing procedure has been described for an end-to-sideanastomosis, it should be appreciated that the procedure is applicableto an end-to-end and side-to-side anastomosis, connecting various tissuestructures including single and multiple tissue structures, and puncturesites, and connecting tissue to a prosthetic graft or valve, forexample.

Bridge clip 1705 can also be used to perform an attachment similar to ahorizontal mattress suture, as is illustrated in FIG. 20. FIG. 20A and20B show a top and a side view, respectively, of bridge clip 1705 usedto perform a horizontal mattress suture. A procedure that may be used toclip the tissue as in FIG. 20 is to aligning tissue edges 2007 and 2009of tissues 2001 and 2003, pierce tissue 2001 and 2003 with piercingmembers 16 to create piercings 2005, and then releasing clips 1703. Whenthis is done, the bridge portion 1705 sits on an outer surface to tissue2001 while the clips 1703 go through the piercings 2005 and wrap aroundthe edges 2007 and 2009 to towards tissue 2001.

It will be observed from the foregoing that the tissue connectorassemblies of the present invention have numerous advantages.Importantly, the assemblies are easier and faster to apply thanconventional sutures that require tying multiple knots. The assembliesalso may be used in minimally invasive procedures including endoscopicprocedures.

All references cited above are incorporated herein by reference.

The above is a detailed description of particular embodiments of theinvention. It is recognized that departures from the disclosedembodiments may be made within the scope of the invention and thatobvious modifications will occur to a person skilled in the art. Thefull scope of the invention is set out in the claims that follow andtheir equivalents. Accordingly, the claims and specification should notbe construed to unduly narrow the full scope of protection to which theinvention is entitled.

1. A surgical method to attach tissue comprising: positioning two piercing ends of a fastener near one side of a first tissue at a piercing distance, where said fastener includes two clips each having an open configuration and a closed configuration, and a bridge portion joining said two clips, where said bridge portion spaces said two clips a clipping distance when in said closed configuration, and where said piercing distance is approximately equal to said clipping distance; piercing said first tissue with said piercing ends with said two clips in said open configuration; positioning said bridge along said one side; piercing a second tissue with said two clips in said open configuration; drawing said clips in said open configuration through said second tissue; and actuating said release mechanism.
 2. The method of claim 1, wherein said self-closing clip includes a shape memory material.
 3. The method of claim 1, wherein said first tissue is the heal or toe of a graft vessel, wherein said second tissue is a target vessel, and wherein said drawing includes parachuting said first tissue onto said second tissue, and wherein said actuating joins said first and second tissue to form an anastomosis.
 4. The method of claim 1, wherein said actuating joins said first and second tissue to form a horizontal mattress suture. 